TWI749429B - Wire electrical discharge machine and control method of wire electrical discharge machine - Google Patents

Abstract

A wire electrical discharge machine (10) for machining a workpiece (12) by generating electric discharge at a discharge gap between the workpiece and a wire electrode (14) includes: a machining current setting unit (26) for setting the magnitude of a normal machining current depending on the discharge gap state at application of a discharge induction voltage at the previous time or previous times; and a machining current control unit (30) configured to control a main discharge circuit (18) so as to supply the normal machining current to the discharge gap when the present discharge gap state is the normal state, control the main discharge circuit (18) so as to supply a short-circuit machining current smaller than a predetermined current to the gap when the discharge gap state is the short-circuited state, and control the main discharge circuit (18) so as not to supply any machining current to the gap when the discharge gap state is the open state.

Description

Metal wire electric discharge machine and control method of metal wire electric discharge machine

The present invention relates to a metal wire electric discharge machine and a control method of the metal wire electric discharge machine for processing the workpiece by generating electric discharge between the workpiece and the metal wire electrode.

A wire electric discharge machine is disclosed in Japanese Patent Publication No. 2017-013151.

In the wire electric discharge machine disclosed in Japanese Patent Publication No. 2017-013151, when the machining current is increased, the machining speed can be increased. However, when the machining current is excessively high, there is a problem that the wire electrode of the metal wire is disconnected frequently.

The present invention was made in order to solve the above-mentioned problems, and its object is to provide a wire electric discharge machine and a control method of a wire electric discharge machine that can suppress wire breakage of the wire electrode and can set the machining current to increase the machining speed.

The first aspect of the present invention is a metal wire electric discharge machine, which generates electric discharge between the electrodes between the workpiece and the metal wire electrode to process the workpiece, and includes a discharge induction circuit, a main discharge circuit, and an inter-electrode state determination Section, inter-electrode state recording section, machining current setting section, and machining current control section, the discharge induction circuit applies a discharge induced voltage to the inter-electrode; the main discharge circuit supplies the machining current to the inter-electrode; the state of the inter-electrode is determined Based on the inter-electrode voltage when the discharge induced voltage is applied to the inter-electrode, the inter-electrode state when the discharge induced voltage is applied to the inter-electrode is determined to be a normal state in which discharge occurs between the poles, and a short-circuit state in which the inter-electrode short-circuit occurs , Or one of the open states in which no power is applied between the electrodes; the inter-electrode state recording section records at least one of the normal state, the short-circuit state, or the open state as the inter-electrode state; the processing current setting The part sets the normal machining current according to the previous state of the inter-electrode; when the state of the inter-electrode is the normal state this time, the machining current control section controls the main discharge circuit to supply the normal machining current to For the inter-electrode, when the state of the inter-electrode this time is the short-circuit state, the main discharge circuit is controlled to supply a short-circuit processing current less than the predetermined current to the inter-electrode, and the state of the inter-electrode this time is the open In the state, the main discharge circuit is controlled so that the machining current is not supplied to the gap.

The second aspect of the present invention is a control method of a metal wire electric discharge machine for processing the workpiece by generating an electric discharge between a workpiece and a metal wire electrode. The metal wire electric discharge machine includes the electrode The discharge induction circuit that applies the discharge induction voltage and supplies the machining current to the main discharge circuit between the electrodes; the control method of the metal wire electric discharge machine includes the step of determining the state of the electrode, the step of recording the state of the electrode, the step of setting the machining current, and the machining The current control step, the step of determining the state of the electrode between the electrodes, is based on the electrode-to-electrode voltage when the discharge induced voltage is applied to the electrode, and determines that the electrode-to-electrode state when the discharge induced voltage is applied to the electrode is normal for the discharge of the electrode. State, the short-circuit state of the inter-electrode short-circuit, or the open state of the inter-electrode; the inter-electrode state recording step records at least one of the normal state, the short-circuit state, or the open state as The inter-electrode state; the processing current setting step sets the normal processing current according to the previous inter-electrode state; the processing current control step is the main discharge circuit when the inter-electrode state is the normal state this time It is controlled to supply the normal machining current to the inter-electrode. When the state of the inter-electrode is the short-circuit state this time, the main discharge circuit is controlled to supply a short-circuit machining current that is less than the predetermined current to the inter-electrode. Next, when the state between the electrodes is the open state, the main discharge circuit is controlled so that the machining current is not supplied to the space.

It can suppress the wire breakage of the metal wire electrode, and can set the processing current to increase the processing speed.

The above-mentioned objects, features, and advantages should be easily understood from the description of the following embodiments described with reference to the attached drawings.

[First Embodiment] [Structure of wire electric discharge machine]

FIG. 1 is a structural diagram of a wire electrical discharge machine 10. The wire electrical discharge machine 10 generates electrical discharge between the workpiece 12 and the wire electrode 14 to process the workpiece 12.

The wire electrical discharge machine 10 includes a discharge induction circuit 16 that applies a discharge induced voltage between the electrodes, a main discharge circuit 18 that supplies machining current to the electrode, an electrode-to-electrode voltage detector 20 that detects the voltage between the electrodes, and a pole-to-electrode voltage determination. The inter-electrode state determination unit 22 of the inter-electrode state, the inter-electrode state recording unit 24 that records the determined inter-electrode state, the machining current setting unit 26 that sets the magnitude of the machining current based on the information of the past inter-electrode state, and the discharge induction circuit 16 A discharge induced voltage control unit 28 that controls the application of a discharge induced voltage between the pair of electrodes, and a machining current control unit 30 that controls the main discharge circuit 18 to supply a machining current to the space between the electrodes.

The discharge induction circuit 16 applies a discharge induction voltage between the electrodes to generate discharge between the electrodes.

After the main discharge circuit 18 generates a discharge between the electrodes, it supplies a machining current for machining the workpiece 12.

The inter-electrode voltage detection unit 20 detects the voltage between the workpiece 12 and the metal wire electrode 14 (inter-electrode voltage) when a discharge induced voltage is applied between the electrodes.

The inter-electrode state determination unit 22 determines the inter-electrode state when the discharge induced voltage is applied to the inter-electrode based on the inter-electrode voltage when the discharge induced voltage is applied to the inter-electrode. The inter-electrode state refers to the normal state where electrical discharge is generated between the electrodes, the short-circuit state caused by the contact between the workpiece 12 and the wire electrode 14, or the machining debris stagnating between the workpiece 12 and the wire electrode 14, and the state where the electrode is not energized. Any one of the open state. The inter-electrode state determination processing of the inter-electrode state determination unit 22 will be described in detail later.

The inter-electrode state recording unit 24 records the inter-electrode state determined by the inter-electrode state determination unit 22 every time a discharge induced voltage is applied to the inter-electrode state.

The machining current setting unit 26 sets the magnitude of the normal machining current described later in accordance with the state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode last time. The state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode last time is recorded in the inter-electrode state recording section 24. The machining current setting process of the machining current setting unit 26 will be described in detail later.

The discharge induction voltage control unit 28 controls the discharge induction circuit 16 to apply a discharge induction voltage of a predetermined voltage between the electrodes in a predetermined cycle.

The machining current control unit 30 controls the main discharge circuit 18 to supply normal machining current or short-circuit machining current as machining current, or not to use machining current, according to the state between the electrodes when the discharge induced voltage is applied between the electrodes this time. Supply to the poles. The machining current control processing of the machining current control unit 30 will be described in detail later. [Interpolar state determination processing]

FIG. 2 is a flowchart showing the flow of the inter-electrode state determination processing performed by the inter-electrode state determination unit 22. The inter-electrode state determination processing is performed during the period during which the discharge induced voltage is applied to the inter-electrode.

In step S1, the inter-electrode state determination unit 22 determines whether the time T1 has elapsed after the discharge induced voltage is applied to the inter-electrode. When the time T1 has elapsed, the process proceeds to step S2, and when the time T1 has not elapsed, the process of step S1 is repeated.

In step S2, the inter-electrode state determination unit 22 determines whether the inter-electrode voltage is equal to or higher than the voltage V1. When the voltage between the electrodes is equal to or higher than the voltage V1, the process proceeds to step S3, and when the voltage between the electrodes is lower than the voltage V1, the process proceeds to step S7.

In step S3, the inter-electrode state determination unit 22 determines whether the inter-electrode voltage is equal to or lower than the voltage V2. When the electrode-to-electrode voltage is below the voltage V2, go to step S4, and when the electrode-to-electrode voltage is greater than the voltage V2, go to step S5.

In step S4, the inter-electrode state determination unit 22 determines that the inter-electrode state is a normal state, and ends the inter-electrode state determination process.

In step S5, the inter-electrode state determination unit 22 determines whether the time T2 has elapsed after the discharge induced voltage is applied to the inter-electrode. When the time T2 has elapsed, the process proceeds to step S6, and when the time T2 has not elapsed, the process returns to step S3.

In step S6, the inter-electrode state determination unit 22 determines that the inter-electrode state is an open state, and ends the inter-electrode state determination process.

In step S7, the inter-electrode state determination unit 22 determines that the inter-electrode state is a short-circuit state, and ends the inter-electrode state determination process. [Waveform of the voltage between the poles in the state of each pole]

Figures 3A to 3C are diagrams showing the waveforms of the inter-electrode voltage in each inter-electrode state. Fig. 3A shows the waveform of the voltage between the electrodes in the normal state. Figure 3B shows the waveform of the voltage between the electrodes in the open state. Fig. 3C shows the waveform of the voltage between the electrodes in the short-circuit state.

First, the waveform of the voltage between the electrodes in the normal state will be explained. In the normal state, just before applying the discharge induced voltage, ensure an appropriate width between the electrodes. The gap between the poles is filled with working fluid, and the gap between the poles is insulated. At this time, when the discharge induced voltage is applied, the inter-electrode voltage rises. As shown in FIG. 3A, the inter-electrode voltage is greater than or equal to the voltage V1. After that, when the metal wire electrode 14 is close to the workpiece 12 and the gap between the electrodes becomes narrow, the insulation between the electrodes is broken and discharge occurs, and the metal wire electrode 14 is electrically connected to the workpiece 12. Therefore, the voltage between the electrodes decreases. As shown in FIG. 3A, the voltage between the electrodes is below the voltage V2 (V2>V1). Therefore, after the discharge induced voltage is applied between the electrodes, the electrode-to-electrode voltage at the time T1 has passed the voltage V1 or more, and the electrode-to-electrode voltage is V2 or less during the period until the time T2 has elapsed. The state between the poles is the normal state.

Next, the waveform of the voltage between the electrodes in the open state will be described. In the open state, just before the discharge induced voltage is applied, the gap between the electrodes is wider than the normal state. Therefore, even if the metal wire electrode 14 is close to the workpiece 12, the gap between the electrodes is not very narrow, so the gap between the electrodes is still in an insulated state, and no discharge occurs. Therefore, as shown in FIG. 3B, after the discharge induced voltage is applied between the electrodes, the voltage between the electrodes does not fall below the voltage V2 even if the time T2 passes. Therefore, the electrode-to-electrode voltage at the elapse of time T1 after the application of the discharge induced voltage to the electrode is above the voltage V1, and when the electrode-to-electrode voltage at the elapse of time T2 is greater than the voltage V2, no discharge occurs between the electrodes, and it can be determined that the state of the electrode is Open state.

Finally, the waveform of the voltage between the electrodes in the short-circuit state will be explained. In the short-circuit state, immediately before the discharge induced voltage is applied, the workpiece 12 is in contact with the wire electrode 14 or machining chips are retained between the workpiece 12 and the wire electrode 14. Therefore, the electrodes are electrically connected from before the discharge induced voltage is applied, and even if the discharge induced voltage is applied, the voltage between the electrodes hardly rises. Therefore, when the electrode-to-electrode voltage at the time T1 elapsed after the discharge induced voltage is applied to the electrode-to-electrode is lower than the voltage V1, it can be determined that the state of the electrode-to-electrode is a short-circuit state.

In addition, as described above, the voltage V2 can be set to be less than the voltage V1, and the voltage V2 can also be set to be equal to the voltage V1. [Processing current setting processing]

4 is a flowchart showing the flow of the machining current setting process performed by the machining current setting unit 26.

In step S11, the machining current setting unit 26 determines whether the inter-electrode state when the discharge induced voltage was applied to the inter-electrode last time is an open state. When it is in the open state, it proceeds to step S13, and when it is in the non-open state, it proceeds to step S12.

In step S12, the machining current setting unit 26 determines whether the state between the electrodes when the discharge induced voltage was applied to the inter-electrodes last time is a short-circuit state. When it is in the short-circuit state, it proceeds to step S13, and when it is in the non-short-circuit state (normal state), it proceeds to step S14.

In step S13, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current, and ends the machining current setting process.

In step S14, the machining current setting unit 26 sets the normal machining current to a predetermined current, and ends the machining current setting process.

In addition, in the flowchart showing the flow of the machining current setting process performed by the machining current setting unit 26 shown in FIG. 4, when the inter-electrode state was an open state when the discharge induced voltage was applied to the inter-electrode last time, it may be a short circuit. In the state, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current. This point can also be that when the inter-electrode state was the open state when the discharge induced voltage was applied to the inter-electrode last time, the machining current setting section 26 sets the normal machining current to be greater than the predetermined current, and the discharge induced voltage was applied to the inter-electrode last time. When the state between the poles is a short-circuit state, the machining current setting unit 26 sets the normal machining current to a predetermined current. Alternatively, the machining current setting unit 26 may set the normal machining current to a predetermined current when the inter-electrode state was the open state when the discharge induced voltage was applied to the inter-electrode last time. When the inter-electrode state is a short-circuit state, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current. [Processing current control processing]

FIG. 5 is a flowchart showing the flow of the machining current control process performed by the machining current control unit 30.

In step S21, the machining current setting unit 26 determines whether the state of the inter-electrode when the discharge induced voltage is applied to the inter-electrode this time is a normal state. When it is in a normal state, it proceeds to step S22, and when it is in an abnormal state, it proceeds to step S23.

In step S22, the machining current setting unit 26 controls the main discharge circuit 18 to supply the normal machining current to the electrode gap, and ends the machining current control process. The normal machining current of the magnitude set by the machining current setting part 26 is supplied to the electrode gap.

In step S23, the machining current setting unit 26 determines whether or not the state of the inter-electrode when the discharge induced voltage is applied to the inter-electrode this time is a short-circuit state. When it is in the short-circuit state, it proceeds to step S24, and when it is in the non-short-circuit state, it proceeds to step S25.

In step S24, the machining current setting unit 26 controls the main discharge circuit 18 to supply the short-circuit machining current between the electrodes, and ends the machining current control process. Supply a short-circuit current that is less than the predetermined current between the poles.

In step S25, the machining current setting unit 26 controls the main discharge circuit 18 so as not to supply the machining current between the electrodes, and ends the machining current control process. [About processing current]

Figure 6A is a graph of the voltage between the electrodes over time. Fig. 6B is a graph showing the change of machining current over time.

As shown in Fig. 6A and Fig. 6B, when the discharge induced voltage is applied between the electrodes this time, the state between the electrodes is normal. When the discharge induced voltage is applied to the previous time, the state is open, the current will be greater than the predetermined current. The normal machining current is supplied between the poles as machining current (refer to machining current MC1). As a result, the amount of processing of the workpiece 12 for one main discharge can be increased.

As shown in Fig. 6A and Fig. 6B, when the discharge induced voltage is applied between the electrodes this time, the state between the electrodes is normal, and when the discharge induced voltage is applied to the previous time, the state is short-circuited, the current will be greater than the predetermined current. The normal machining current is supplied between the poles as machining current (refer to machining current MC2). As a result, the amount of processing of the workpiece 12 for one main discharge can be increased.

As shown in Figures 6A and 6B, the state of the inter-electrode when the discharge induced voltage is applied between the electrodes is normal. The equal normal machining current is supplied between the poles as machining current (refer to machining current MC3). Thereby, the disconnection of the metal wire electrode 14 caused by the main discharge can be suppressed.

As shown in Figure 6A and Figure 6B, when the inter-electrode state when the discharge induced voltage is applied to the inter-electrodes this time is a short-circuit state, a short-circuit machining current less than the predetermined current is supplied to the inter-electrode as machining current (refer to machining current MC4, MC5) . Thereby, the metal wire electrode 14 can be separated from the workpiece 12 by the impact of the main discharge, or the machining chips remaining between the workpiece 12 and the metal wire electrode 14 can be removed.

Fig. 7A and Fig. 7B are diagrams for explaining the method of adjusting the magnitude of the machining current. Figure 7A shows the processing current of the triangular wave. Figure 7B shows the processing current of the trapezoidal wave. The magnitude of the processing current is adjusted by the turn-on time of the switching element not shown in the figure of the main discharge circuit 18. In this embodiment, a triangular wave or a trapezoidal wave is used as the processing current, and processing currents of other waveforms may also be used. [Effect]

In order to increase the processing speed of the workpiece 12 by the wire electrical discharge machine 10, it is only necessary to increase the processing current. However, when the machining current is increased, the possibility of wire breakage of the wire electrode 14 increases.

The applicant of this case focused on the fact that it is an open state when the discharge induced voltage is applied, and the machining current is not supplied to the inter-electrode. Therefore, the amount of energy input per unit time between the electrodes is reduced. In the wire electrical discharge machine 10 of this embodiment, the machining current setting unit 26 sets the normal machining current according to the state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode before the previous time. Specifically, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current when the inter-electrode state when the discharge induced voltage is applied to the inter-electrode last time is an open state. Next, when the inter-electrode state when the discharge induced voltage is applied to the inter-electrode this time is a normal state, the machining current control unit 30 controls the main discharge circuit 18 to supply the set normal machining current to the inter-electrode. Thereby, the time average of the energy input amount can be increased, the processing speed of the workpiece 12 of the wire electric discharge machine 10 can be increased, and the possibility of wire breakage of the wire electrode 14 can be reduced.

In addition, in the wire electrical discharge machine 10 of the present embodiment, the machining current setting unit 26 sets the magnitude of the normal machining current only based on the state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode last time. Thereby, the processing current setting process of the processing current setting part 26 can be made simple.

In addition, in the wire electrical discharge machine 10 of this embodiment, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current when the inter-electrode state when the discharge induced voltage was applied to the inter-electrode last time is a short-circuit state. When the discharge induced voltage is applied, when it is in a short-circuit state, a short-circuit machining current less than a predetermined current is supplied to the gap between the electrodes, so the energy input per unit time between the electrodes is reduced. When the inter-electrode state when the discharge induced voltage is applied to the inter-electrode last time is a short-circuit state, the machining current setting unit 26 sets the normal machining current to be greater than the predetermined current. Thereby, the time average of the energy input amount can be increased, the processing speed of the workpiece 12 of the wire electric discharge machine 10 can be increased, and the possibility of wire breakage of the wire electrode 14 can be reduced. [Second Embodiment]

In the first embodiment, the normal machining current is set based only on the state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode last time. It can also be based on the inter-electrode state when the discharge induced voltage is applied to the inter-electrode multiple times before the previous time. Status, set the size of the normal processing current.

In the wire electrical discharge machine 10 of the present embodiment, the machining current setting unit 26 sets the normal machining current to be larger as the number of consecutive times that the inter-electrode state is an open state when the discharge induced voltage is applied to the inter-electrode before the current time. .

Figure 8A is a graph of the voltage between the electrodes over time. Fig. 8B is a graph showing the change of machining current over time. As shown in Fig. 8A and Fig. 8B, compared to the normal machining current when the inter-electrode state before the previous time is open, the number of consecutive times is 2 times, when the previous inter-electrode state is open state for 5 times Set the normal machining current to be larger (refer to machining current MC11, MC12). [Effect]

The more consecutive times that the inter-electrode state is an open state, the more the energy input per unit time between the poles decreases. Therefore, in the wire electrical discharge machine 10 of this embodiment, the machining current setting unit 26 sets the normal machining current as the number of consecutive times that the inter-electrode state is open when the discharge induced voltage is applied to the inter-electrode before the current time. For the bigger. Thereby, the time average of the energy input amount can be increased, the processing speed of the workpiece 12 of the wire electric discharge machine 10 can be increased, and the possibility of wire breakage of the wire electrode 14 can be reduced. [Third Embodiment]

In the first embodiment, the normal machining current is set based only on the state of the inter-electrode when the discharge induced voltage was applied to the inter-electrode last time. It can also be based on the inter-electrode state when the discharge induced voltage is applied to the inter-electrode multiple times before the previous time. Status, set the size of the normal processing current.

In the wire electrical discharge machine 10 of the present embodiment, the machining current setting section 26 applies the discharge induced voltage to the inter-electrode a predetermined number of times before the previous time, and the more the inter-electrode state is in the open state, the normal machining current Set to be larger.

Figure 9A is a graph of the voltage between the electrodes over time. Fig. 9B is a graph showing the change of machining current over time. As shown in FIGS. 9A and 9B, compared to the normal machining current when the inter-electrode state is open for a predetermined number of times (for example, 4 times) before the previous time, the inter-electrode state is a predetermined number of times before the previous time. The normal machining current when the number of times of being in the open state is 3 is set to be large (refer to machining current MC21, MC22). [Effect]

Within the predetermined number of times, the more the number of times the inter-electrode state is in the open state, the more the energy input per unit time between the electrodes decreases. Therefore, in the wire electrical discharge machine 10 of the present embodiment, the machining current setting section 26 applies the discharge induced voltage to the electrode a predetermined number of times before the previous time, and the more the inter-electrode state becomes the open state, the more The normal machining current is set to be larger. Thereby, the time average of the energy input amount can be increased, the processing speed of the workpiece 12 of the wire electric discharge machine 10 can be increased, and the possibility of wire breakage of the wire electrode 14 can be reduced. [Fourth Embodiment]

In the wire electrical discharge machine 10 of the first embodiment to the third embodiment, the magnitude of the normal machining current is set based on the state of the inter-electrode when a discharge induced voltage is applied to the inter-electrode before the previous time. In contrast, in the wire electrical discharge machine 10 of the present embodiment, the machining current setting unit 26 sets the normal setting when the discharge delay time between the discharge induced voltage is applied to the electrode gap and the discharge is generated between the electrodes is longer. The machining current is corrected to be larger.

Figure 10A is a graph of the voltage between the electrodes over time. Fig. 10B is a graph showing the change of machining current over time. As shown in Fig. 10A and Fig. 10B, when the inter-electrode state was normal when the discharge induced voltage was applied to the inter-electrode last time, the discharge delay from when the discharge induced voltage was applied to the inter-electrode this time until the discharge occurred in the inter-electrode The longer the time, the greater the normal machining current set (refer to the machining current MC31, MC32).

As shown in Fig. 10A and Fig. 10B, when the inter-electrode state when the discharge induced voltage was applied to the inter-electrode last time was an open state, the discharge delay after the discharge induced voltage is applied to the inter-electrode this time until the discharge occurs in the inter-electrode The longer the time, the greater the normal machining current set (refer to the machining current MC33, MC34).

As shown in Fig. 10A and Fig. 10B, when the inter-electrode state was a short-circuit state when the discharge induced voltage was applied to the inter-electrode last time, the discharge delay until the discharge occurs in the inter-electrode after the discharge induced voltage is applied to the inter-electrode this time The longer the time, the greater the normal machining current set (refer to the machining current MC35, MC36). [Effect]

The longer the discharge delay time after the discharge induced voltage is applied between the electrodes until the discharge occurs between the electrodes, the lower the energy density between the electrodes can be estimated. Therefore, in the wire electrical discharge machine 10 of this embodiment, the machining current setting unit 26 applies the discharge induced voltage to the electrode gap this time until the discharge is generated between the electrodes, the longer the discharge delay time, the normal machining current The correction becomes larger. Thereby, the time average of the energy input amount can be increased, the processing speed of the workpiece 12 of the wire electric discharge machine 10 can be increased, and the possibility of wire breakage of the wire electrode 14 can be reduced. [Technical Ideas Obtained from the Implementation Mode]

The technical ideas that can be grasped from the above-mentioned embodiments are described below.

A metal wire electrical discharge machine (10), which generates electrical discharge between the workpiece (12) and the metal wire electrode (14) to process the workpiece, and includes a discharge induction circuit (16) and a main discharge circuit ( 18) Inter-electrode state determination section (22), inter-electrode state recording section (24), machining current setting section (26), and machining current control section (30), the discharge induction circuit applies a discharge induced voltage to the inter-electrode ; The main discharge circuit supplies the machining current to the pole; the inter-electrode state determination section determines the state of the inter-electrode when the discharge induced voltage is applied to the pole based on the inter-electrode voltage when the discharge induced voltage is applied to the pole Is the normal state of discharge between the electrodes, the short-circuit state of the inter-electrodes, or the open state of the inter-electrodes; the inter-electrode state recording section records the normal state, the short-circuit state, or At least one of the open states is regarded as the inter-electrode state; the machining current setting part sets the normal machining current according to the previous inter-electrode state; the machining current control part is in the normal state when the inter-electrode state is the normal state this time , The main discharge circuit is controlled to supply the normal machining current to the inter-electrode, and when the state of the inter-electrode this time is the short-circuit state, the main discharge circuit is controlled to supply the short-circuit machining current less than the predetermined current to the For the inter-electrode, when the state of the inter-electrode is the open state this time, the main discharge circuit is controlled so that the machining current is not supplied to the inter-electrode.

In the above-mentioned wire electrical discharge machine, the inter-electrode state recording section may also record at least the open state, and the machining current setting section sets the normal machining current to at least when the previous inter-electrode state is the open state More than the predetermined current.

In the above-mentioned metal wire electric discharge machine, the machining current setting part can also set the normal machining current based on the previous state of the inter-electrode.

In the above-mentioned wire electric discharge machine, the machining current setting unit may also set the normal machining current to be larger as the number of consecutive times that the inter-electrode state before the current time is the open state is greater.

In the above-mentioned wire electric discharge machine, the machining current setting unit may also set the normal machining current to be larger as the ratio of the inter-electrode state to the open state a predetermined number of times before the current time is greater.

In the above-mentioned metal wire electric discharge machine, the inter-electrode state recording section may also record at least the short-circuit state, and the processing current setting section sets the normal processing current to at least when the previous inter-electrode state is the short-circuit state More than the predetermined current.

In the above-mentioned metal wire electric discharge machine, the machining current setting unit can also set the normal machining current when the discharge induced voltage is applied to the electrode between the electrodes, the longer the discharge delay time until the discharge is generated between the electrodes. The correction becomes larger.

A method for controlling a metal wire electric discharge machine (10). The metal wire electric discharge machine generates an electric discharge between a workpiece (12) and a metal wire electrode (14) to process the workpiece. The metal wire discharges The processing machine includes a discharge induction circuit (16) that applies a discharge induction voltage to the electrode, and a main discharge circuit (18) that supplies a machining current to the electrode; the control method of the metal wire electric discharge machine includes the determination of the state of the electrode Step, inter-electrode state recording step, processing current setting step, processing current control step. The inter-electrode state determination step determines the application of the discharge induced voltage to the inter-electrode based on the inter-electrode voltage when the discharge induced voltage is applied to the inter-electrode The inter-electrode state at the time is the normal state of discharge between the poles, the short-circuit state of the inter-electrode short-circuit, or the open state of the inter-electrode; the inter-electrode state recording step records the normal state , At least one of the short-circuit state or the open state is regarded as the inter-electrode state; the processing current setting step sets the normal processing current according to the inter-electrode state before the previous time; the processing current control step is in the current When the inter-electrode state is the normal state, the main discharge circuit is controlled to supply the normal machining current to the inter-electrode. When the inter-electrode state is the short-circuit state this time, the main discharge circuit is controlled to be less than A short-circuit machining current of a predetermined current is supplied to the inter-electrode, and when the state of the inter-electrode this time is the open state, the main discharge circuit is controlled to not supply the machining current to the inter-electrode.

In the above-mentioned control method of a metal wire electric discharge machine, the inter-electrode state recording step can also record at least the open state, and the processing current setting step is at least the normal processing when the previous inter-electrode state is the open state. The current is set to be greater than the predetermined current.

In the above-mentioned control method of the metal wire electric discharge machine, the processing current setting step can also set the normal processing current only based on the previous state of the inter-electrode.

In the above-mentioned control method of the wire electrical discharge machine, the machining current setting step can also set the normal machining current to be larger as the number of consecutive times that the inter-electrode state before the current time is the open state is greater.

In the above-mentioned control method of the wire electrical discharge machine, the machining current setting step can also set the normal machining current to be larger as the ratio of the inter-electrode state to the open state for a predetermined number of times before the current time is greater.

In the above-mentioned control method of a metal wire electric discharge machine, the inter-electrode state recording step can also record at least the short-circuit state, and the processing current setting step is at least the normal processing when the previous inter-electrode state is the short-circuit state. The current is set to be greater than the predetermined current.

In the above-mentioned control method of the metal wire electric discharge machine, the machining current setting step can also be used when the discharge induced voltage is applied to the electrode between the electrodes until the discharge is generated between the electrodes as the discharge delay time becomes longer. The normal processing current is corrected to be larger.

10: Metal wire electric discharge machine 12: Workpiece 14: Metal wire electrode 16: Discharge induction circuit 18: Main discharge circuit 20: Inter-electrode voltage detection section 22: Inter-electrode state determination section 24: Interpolar state recording department 26: Machining current setting section 28: Discharge induction voltage control unit 30: Processing current control unit MC1: Processing current MC2: Processing current MC3: Processing current MC4: Processing current MC5: Processing current MC11: Processing current MC12: Processing current MC21: Processing current MC22: Processing current MC31: Processing current MC32: Processing current MC33: Processing current MC34: Processing current MC35: Processing current MC36: Processing current S1: Step S2: Step S3: steps S4: Step S5: Step S6: steps S7: steps S11: steps S12: steps S13: steps S14: Step S21: Step S22: Step S23: Step S24: steps S25: steps T1: time T2: time V1: Voltage V2: Voltage

Figure 1 is a structural diagram of a wire electrical discharge machine. Fig. 2 is a flowchart showing the flow of the inter-electrode state determination processing performed by the inter-electrode state determination unit. Figures 3A to 3C are diagrams showing the waveforms of the inter-electrode voltage in each inter-electrode state. Fig. 4 is a flowchart showing the flow of the machining current setting process performed in the machining current setting section. Fig. 5 is a flowchart showing the flow of the machining current control processing performed by the machining current control section. Figure 6A is a graph of the voltage between the electrodes over time. Fig. 6B is a graph showing the change of machining current over time. Fig. 7A and Fig. 7B are diagrams for explaining the method of adjusting the magnitude of the machining current. Figure 8A is a graph of the voltage between the electrodes over time. Fig. 8B is a graph showing the change of machining current over time. Figure 9A is a graph of the voltage between the electrodes over time. Fig. 9B is a graph showing the change of machining current over time. Figure 10A is a graph of the voltage between the electrodes over time. Fig. 10B is a graph showing the change of machining current over time.

10: Metal wire electric discharge machine

12: Workpiece

14: Metal wire electrode

16: Discharge induction circuit

18: Main discharge circuit

20: Inter-electrode voltage detection section

22: Inter-electrode state determination section

24: Interpolar state recording department

26: Machining current setting section

28: Discharge induction voltage control unit

30: Processing current control unit

Claims (14)

A metal wire electric discharge machine (10), which generates electric discharge between the electrode between a workpiece (12) and a metal wire electrode (14) to process the workpiece, and includes: a discharge induction circuit (16) for the electrode Discharge induced voltage is applied; the main discharge circuit (18) supplies machining current to the electrode; the inter-electrode state determination section (22) determines the electrode based on the electrode-to-electrode voltage when the discharge induced voltage is applied to the electrode The inter-electrode state when the discharge induced voltage is applied between the electrodes is the normal state of discharge between the electrodes, the short-circuit state of the inter-electrode short circuit, or the open state of the inter-electrode without electricity; the state of the inter-electrode state is recorded Section (24), which records at least one of the normal state, the short-circuit state, or the open state as the inter-electrode state; the machining current setting section (26) sets the normal machining current according to the previous state of the inter-electrode Size; and the processing current control unit (30), when the state of the inter-electrode is the normal state this time, controls the main discharge circuit to supply the normal processing current to the inter-electrode; in the state of the inter-electrode this time When it is the short-circuit state, control the main discharge circuit to supply a short-circuit machining current less than the predetermined current to the inter-electrode; when the inter-electrode state is the open state this time, control the main discharge circuit so as not to process the Electric current is supplied between the poles. For example, the metal wire electrical discharge machine of item 1 of the scope of patent application, wherein the inter-electrode state recording section records at least the open state, and the machining current setting section at least the previous time when the inter-electrode state was the open state. The normal machining current is set to be greater than the predetermined current. For example, the metal wire electric discharge machine of item 1 or item 2 of the scope of patent application, wherein the processing current setting part only sets the magnitude of the normal processing current based on the previous state of the inter-electrode. For example, the metal wire electric discharge machine of the second item of the scope of patent application, wherein, the more consecutive times the inter-electrode state is the open state before the current time, the processing current setting unit sets the normal processing current to be larger. For example, the metal wire electrical discharge machine of the second item of the scope of patent application, wherein, the greater the ratio of the inter-electrode state to the open state for the predetermined number of times before the current time, the greater the processing current setting unit sets the normal processing current to big. For example, the metal wire electric discharge machine of any one of items 1, 2, 4, and 5 in the scope of patent application, wherein the inter-electrode state recording section records at least the short-circuit state, and at least the previous inter-electrode state is the short-circuit In the state, the machining current setting unit sets the normal machining current to be greater than the predetermined current. For example, the metal wire electric discharge machine of any one of items 1, 2, 4, and 5 in the scope of the patent application, wherein, when the discharge induced voltage is applied to the electrode between the electrodes this time, the discharge delay until the discharge is generated between the electrodes The longer the time, the processing current setting unit corrects the normal processing current to be larger. A method for controlling a metal wire electric discharge machine (10). The metal wire electric discharge machine generates an electric discharge between a workpiece (12) and a metal wire electrode (14) to process the workpiece. The metal wire discharges The processing machine includes: a discharge induction circuit (16), which applies a discharge induction voltage to the electrode; a main discharge circuit (18), which supplies a machining current to the electrode; the control method of the metal wire electric discharge machine includes: The inter-electrode state determination step is to determine the inter-electrode state when the discharge induced voltage is applied to the inter-electrode is the normal state in which the discharge is generated between the electrodes, and the inter-electrode state when the discharge induced voltage is applied to the inter-electrode. One of the short-circuit state of an inter-electrode short circuit or an open state in which no current is applied between the poles; an inter-electrode state recording step, recording at least one of the normal state, the short-circuit state, or the open state as the inter-electrode state ; Processing current setting step, set the normal processing current according to the previous state of the inter-electrode; and processing current control step, when the state of the inter-electrode this time is the normal state, control the main discharge circuit to The normal machining current is supplied to the inter-electrode; when the state of the inter-electrode this time is the short-circuit state, the main discharge circuit is controlled to supply a short-circuit machining current less than the predetermined current to the inter-electrode; in the inter-electrode state this time When the state is the open state, the main discharge circuit is controlled so as not to supply the machining current to the inter-electrode. For example, the control method of the metal wire electrical discharge machine in the scope of patent application, wherein the inter-electrode state recording step records at least the open state, and the machining current setting step is at least when the previous inter-electrode state is the open state , Set the normal machining current to be greater than the predetermined current. For example, the control method of the metal wire electric discharge machine of the 8th or 9th item of the scope of patent application, wherein the processing current setting step is only based on the previous state of the inter-electrode to set the normal processing current. For example, the control method of the metal wire electric discharge machine in the scope of patent application, wherein, the more the number of consecutive times that the current state of the inter-electrode is the open state, the processing current setting step sets the normal processing current to Bigger. For example, the control method of the metal wire electric discharge machine in the 9th item of the scope of patent application, among which, The greater the ratio of the inter-electrode state to the open state for a predetermined number of times before the current time, the greater the processing current setting step sets the normal processing current. For example, the control method of a metal wire electric discharge machine in any one of items 8, 9, 11, and 12 in the scope of patent application, wherein the inter-electrode state recording step records at least the short-circuit state, at least the state of the inter-electrode in the previous time In the short-circuit state, the machining current setting step sets the normal machining current to be greater than the predetermined current. For example, the control method of the metal wire electric discharge machine of any one of items 8, 9, 11, and 12 in the scope of patent application, wherein, when the discharge induced voltage is applied to the electrode between the electrodes this time, until the discharge is generated between the electrodes The longer the discharge delay time is, the larger the processing current setting step will be to correct the normal processing current.

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